Tachycardia is characterized by a heart rate greater than 100 beats per minute. There are many variants of this clinical entity, with different prognoses.
In order for cardiac contraction to occur, the nervous system follows a series of rather complex steps. The rhythm of electrical impulses begins in the automated neurons at the sinus node, located in the right atrium of the heart. In different ways, this impulse reaches the atrioventricular (AV) node, which in turn ends up splitting on the left and right branch of the bundle of His. Each branch incurs in the left and right ventricles, and the Purkinje cells on each side are the ones that cause ventricular depolarization.
Explained quickly and running, this is the mechanism that causes the contraction of the ventricles and, therefore, the onset of the heartbeat. The normal rate at which all these events occur is 60 to 100 contractions per minute, but why a significant increase in heart rate? To answer this question and many more, we address in the following lines the 5 types of tachycardias and their characteristics. Don’t miss it.
- We recommend you read: “Nocturnal tachycardia due to fear or anxiety: causes and treatment”
What is a tachycardia and what are its types?
Depending on age, a normal heart rate can vary. For example, a 1- to 3-week-old baby may have a heart rate of 160 beats per minute and this may not be a problem. In any case, in humans, a rate of atrial and/or ventricular contraction greater than 100 beats per minute (tachycardia) or less than 60 (bradycardia) is considered abnormal. In addition, the established cut-off point depends on the patient’s underlying condition. For example, when sepsis is passing, any value greater than 90 beats per minute is considered tachycardia.
Tachycardia can be physiological or pathologicaltag. In the first case, the person who suffers from it is responding normally to an exogenous stimulus through intense emotion. For example, when we hear a loud noise and feel in danger, one of the first hormones to kick in is adrenaline. This increases the heart rate (tachycardia), constricts blood vessels, dilates the airways and prepares us to fight or run.
This physiological response is considered normal in humans, and therefore physiological tachycardias do not necessarily decrease life expectancy or pose a long-term problem. However, things change when this rapid heart rate is caused by depression, chronic anxiety, kidney failure, anemia, severe bleeding or cardiac shock. Based on these premises, we present the 5 types of tachycardias.
1. Atrial fibrillation (AF)
In this variant, the heart beats very fast and at an irregular rate. Most episodes are asymptomatic, but sometimes dizziness, palpitations, shortness of breath and chest pain may be felt. It correlates with clinical entities such as hypertension and congenital valve diseases (valvular heart disease).
It is the most common type of arrhythmia (and therefore tachycardia) in the entire general population. In addition, it is divided into 3 different variants, depending on the degree of establishment of the clinical sign:
- Paroxysmal AF: of short duration. It does not exceed 7 days and disappears spontaneously.
- Persistent AF– Does not go away on its own and lasts more than 7 days. In this case, it is necessary to resort to medication.
- Chronic AF: the most worrying variant of all. It is progressive onset and does not respond to outpatient treatment.
In all variants, antiarrhythmic drugs (pharmacological cardioversion) or electric shocks with a defibrillator (electrical cardioversion) are used in the first instance. Furthermore,if the fibrillation is caused by an underlying clinical entity, this should also be treated.
2. Atrial flutter
An abnormal heart rhythm that leads to fast heart rhythms, such as supraventricular tachycardia. It is very common in people with basal problems in the circulatory system, such as cardiomyopathy, ischemic heart disease or hypertension, among many other clinical entities. In this particular setting, a premature electrical current is generated in the atrium and this causes a perpetual feedback within the atrial region.
At first, atrial flutter is well tolerated, but little by little it generates symptoms in patients with existing heart disease, such as chest pain, dizziness, nausea, anxiety, and many other clinical conditions. A prolongation of the flutter can lead to heart failure, so cardioversion is often necessary as well.
3. Supraventricular tachycardia (PSVT)
In this case, the heart rhythms are excessively fast but regular, due to problems that lie in the branches of the bundle of His, named in the first lines of this space. It manifests with anxiety, chest tightness, rapid pulse, shortness of breath, dizziness, fainting, etc. It is not always a serious clinical entity, but the fact that the heart rate can reach 250 beats per minute requires, at a minimum, constant monitoring.
In addition, PSVT is intermittent, so a patient experiencing PSVT must wear a 24-hour Holter monitor for some time to receive the correct diagnosis. You can try to stop this tachycardia with some home remedies, but if it does not stop, a visit to the emergency room and the injection of intravenous medications is necessary.
4. Ventricular tachycardia
Ventricular tachycardia is accompanied by other clinical entities of a cardiac nature that already cause symptoms on their own, such as shortness of breath, fainting or chest pain. It is an extrasystolic event in the ventricle, or what is the same, that there is a depolarization and contraction earlier than normal in the ventricular environment.
In general, this cardiac imbalance is experienced in the form of an unusual strong beat, but then the heart recovers itsphysiological stability on its own. If the ventricular tachycardia lasts more than 30 seconds, it is considered sustained.
In this clinical picture, things get a bit more complicated, since it is not only about avoiding an abnormal heart rhythm, but about minimizing the chances of sudden death (remember that this tachycardia is accompanied by previous conditions). Therefore, a cardioverter defibrillator (CDI) is usually implanted in the patient, whose purpose is to detect spontaneous arrhythmia and correct it. ICDs constantly and continuously monitor the heart, thus preventing death from serious arrhythmias.
5. Ventricular fibrillation
One of the most serious tachycardias in the clinical settingtag. The ventricular rhythm is extremely fast (more than 250 beats per minute), which leads to the absence of normal contraction, a chaotic rhythm, the lack of blood in the body and, therefore, the death of the patient. It is the final rhythm of almost all sudden deaths, and it appears as the hallmark of death in practically all heart diseases.
In 80% of cases, ventricular fibrillation arises from severe ischemic heart disease. The only possible treatment is an emergency defibrillation, but you have to be quick: every minute that passes, the chances of survival are reduced by 15%.
Summary
As you have seen, a pathological tachycardia can go from a strong heartbeat to death in a matter of minutes. You must bear in mind that most of them are preceded by a heart problem or valve disease, so patients who present them are on the alert and usually have medications and protocols at hand to prevent heart rhythm imbalances from ending badly. In any case, atrial fibrillation is usually a sign of death in almost all cases, whether or not you are prepared for it.
Finally, we want to emphasize that not all tachycardias are badtag. If you feel constantly agitated and after doing the pertinent tests (electrocardiogram) everything has gone well, it is most likely that you have anxiety and continued stress over time. In these cases, the answer is found in a psychological clinic and not in the cardiologist.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
